This invention relates to the art of valving, particularly to a valve having a rotatable handle for operating an axially movable stem. Examples of such valves are in the present applicant's prior patents, U.S. Pat. No. 4,601,310 and U.S. Pat. No. 4,907,780.
In valves of this type, it is common to provide the handle and/or the stem with helical threads, to convert rotary motion of the handle to linear motion of the stem, and to provide force multiplication. In cases where great force multiplication is not necessary, however, the threaded mechanism can provide objectionably slow response, so that many turns of the handle are necessary to open or close the valve. This invention is directed at increasing the actuating speed of such a valve.